求证tan(a+π/4)=(1+tana)/(1-tana)
tan(a+b)-1/tana=2*tana 请化简!
求证tan(A/2)-{1/(tanA/2)}=-2/tanA
求证tan(a/2)-1/(tana/2)=-2/tana
求证sin^2a*tana+cos^2a*1/tana+2sina*cosa=tana+1/tana
tan²a-2tana-3=0.tana=3或tana=-1
tan(A+B) = (tanA+tanB) / (1-tanA * tanB) = -1从而得到:tanA+tanB
tanA=-1 A=多少度,
tanA=1/2 A 等于多少
tanA=1/4,如何求A?
tan(A+90°)=-1/tanA
tan(90+a)=-1/tana